Waterproofing article for concrete joints

Abstract: A shaped, water-expandable water-sealing article (12) used for sealing an area between a first section (32) of at least partially cured concrete and a second, adjacent section (34) of substantially uncured concrete to form a plurality of water-sealed concrete sections. The clay water sealing article (12) is in the shape of quadrilateral, preferably a trapezoid, and is disposed to bridge an area between the two sections of concrete. Upon hydration of the clay contained within the shaped water sealing article, expansion of the clay creates expansion forces extending from a corner of the article that is surrounded by the uncured concrete, wherein the corner has an included angle greater than 90°, preferably at least 100°. The expansion force developed by the expansion of the shaped water sealing article are absorbed by a substantially increased area of the uncured concrete as compared to expansion forces resulting from a clay-based water seal having a 90° included angle at the corner (s) surrounded by the uncured concrete.

Description: The present invention relates to a shaped waterproofing article containing a water-swellable clay, such as sodium bentonite, for constructing and waterproofing concrete joints. More specifically, the present invention is directed to a shaped water-swellable clay-containing water seal article and a method of waterproofing wherein the article is disposed in contact with a first section of partially or completely cured concrete, and then another concrete section is poured adjacent to the first concrete section such that the shaped article bridges the two concrete sections and is capable of swelling to prevent water seepage between the concrete sections. In constructing various structures with cement compositions, e.g., concrete, it is often necessary to seal, or waterproof, the joints between adjacent sections of concrete. For example, water seals typically are used, in the construction of concrete sections, where concrete joints become necessary. such water seals are common between two preformed or precured concrete sections, or at a joint between one precured or partially cured concrete section and a concrete section being poured. More specifically, waterproofing articles for sealing concrete joints, for example, may be used during construction of the following structures: precast concrete wall systems; septic tanks and sewage treatment plants; sanitary and storm sever manholes; pipe, including round, oval, flatbase, elliptical and arch types; cold joints in foundation slabs or walls below grade; burial and utility vaults; wet wells; box culverts; waste water treatment plants; and portable water tanks. A functional waterproofing seal should provide a complete water barrier to prevent water infiltration. Joints between adjacent concrete sections, such as those used during the construction of the above-mentioned structures, may be made as socket-and-plug or male-femalc type joints. These joint types sometimes are particularly problemsome in providing a complete waterproof seal due to insufficient dimensional accuracy, improper field work at the construction site, and/or uneven settling of the land on which the concrete structure is placed. When a water-expandable waterproofing composition is disposed to bridge the joint between (a) a cured or partially cured section of concrete and (b) a newly poured concrete section, being poured adjacent to the cured or partially cured concrete section, expansion of the waterproofing composition results in forces against one or both of the concrete sections from the expanding waterproofing composition. The shaped waterproofing composition of the present invention minimizes the stress and/or expansion forces exerted against one or both of the adjacent concrete sections from the expanding waterproofing article. Another substantial problem frequently encountered when using a water-expandable, waterproofing article to seal a joint between two concrete sections is that the waterproofing article can be deformed or displaced from its intended position at the joint. Deformation and/or displacement can result since the waterproofing article is formed from a composition that is relatively soft and can be deformed and, or displaced easily upon impact from concrete being poured onto the composition. For example, when a water seal article is placed on an upper surface of a first concrete section that is at least partially cured, and a second concrete section is newly poured adjacent to the first concrete section, the falling concrete that impacts the water seal article oftentimes forces the article out of place, so that the article no longer bridges the two concrete sections completely along this joint. A useful water seal article should have additional beneficial qualities. Such a seal should be useful in all environmental temperatures encountered at the installation location without becoming too stiff and brittle in cold temperatures, and without becoming so soft at higher temperatures that the composition slows by gravity and is thereby displaced from its intended location. Also, the seal should remain flexible over time without shrinking, substantial hardening or oxidizing. Further, a water seal article should be safe to use. Bentonite clay, particularly sodium bentonite, often has been used in waterproofing applications, including foundation waterproofing, due to its known ability to expand, upon hydration, to fill areas of potential water flow. Bentonite clay swells to many times its non-hydrated volume when it comes into contact with water, forming a water-impenetrable clay layer that protects an adjacent structure. The hydrated clay composition expands sufficiently to seal relatively large seams or joints between concrete sections as well as relatively small cracks in concrete. Installing water seals in concrete joints has been a time consuming and labor-intensive part of concrete construction. Therefore, a useful seal should not only allow for a complete, quality seal between concrete sections, but it should be capable of relatively easy and cost-efficient installation. The water seal of the present invention satisfies all of the criteria set forth above. In brief, the present invention is directed to a shaped water-swellable clay-containing water sealing article used for sealing an area between a first section of at least partially cured concrete and a second, adjacent section of substantially uncured concrete. The clay water sealing article of the present invention is in the shape of a quadrilateral, preferably a trapezoid, and is disposed to bridge an area between a section of at least partially cured concrete and a newly poured, substantially uncured section of concrete. Upon hydration of the clay contained within the shaped water seal article, expansion of the clay creates forces upon the adjacent concrete section(s). The expansion forces extend from a corner of the waterproofing article that is surrounded by the uncured concrete, wherein the corner has an included angle greater than 90°. The concrete forces, resulting from the expansion of the shaped water seal article of the present invention, are applied to a substantially increased area as compared to forces resulting from a clay-based water seal article having a 90° included angle at the corner(s) surrounded by the uncured concrete. Accordingly, an aspect of the present invention is to provide a shaped water-swellable clay-containing water seal article that contains at least about 20% by weight of a water-swellable bentonite clay, such as sodium bentonite, for sealing an area between two concrete sections, one cured, and an adjacent, substantially uncured concrete section, while minimizing forces applied against any uncured concrete surrounding the shaped waterproofing article. Another aspect of the present invention is to provide adjacent, water sealed concrete sections including a first section of at least partially cured concrete; a second section of substantially uncured concrete; and an elongate strip of a bentonite clay-containing water seal article, located between the two sections, said article having a vertical cross-sectional area defining a quadrilateral, having at least one uncured concrete-surrounded corner, said uncured concrete surrounded corner having an included angle greater than 90° and, preferably, at least 100°. Still another aspect of the present invention is to provide a method of waterproofing an area of potential water leakage, between concrete sections, with a clay water seal strip having a vertical cross-sectional shape, perpendicular to a longitudinal axis of the strip, in the shape of a trapezium, preferably a trapezoid. A further aspect of the present invention is to provide a method of waterproofing an area of potential water leakage between adjacent sections of concrete comprising forming a first section of at least partially cured concrete, disposing the clay water seal material in contact with the concrete, and then pouring a second section of substantially uncured concrete onto an upper surface of the water seal material, wherein the clay water seal has a vertical cross-sectional shape of a trapezium, preferably a trapezoid, disposed between the two concrete sections and bridging the area of potential water leakage. Other aspects, features and advantages are inherent in the articles and methods as claimed and disclosed or will become inherent to those of ordinary skill in the art in view of the detailed description of the preferred embodiments, which is made with reference to the drawing, a brief description of which is provided below. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT In accordance with the present invention, a shaped water-swellable clay water sealing article, containing aL least about 20% by weight of water-swellable bentonite clay, is used for sealing an area between an at least partially cured concrete section and a section of substantially uncured concrete. Preferably, the uncured concrete section is poured above, or horizontally adjacent to, and in contact with the cured or partially cured concrete section. The clay water sealing article of the present invention is in the shape of a quadrilateral having, at most, two parallel surfaces, preferably in the shape of a trapezium, and more preferably in the shape of a trapezoid, to minimize forces acting on a surrounding uncured concrete section as a result of expansion of the water seal article. Upon hydration of the water seal article, expansion forces against the newly poured concrete section extend upwardly and outwardly from the corner (s) of the water seal article surrounded by the newly poured conorete. The corner(s) (defined by an intersection of a side surface and an upper surface of the clay seal article) of the water seal article of the present invention that are surrounded by the freshly poured concrete should have an included angle greater than 90°, preferably about 100° to about 150°, e.g., about 110° to about 140°, and most preferably about 130°. The expansion forces developed using the shaped waters seal article of the present invention are absorbed over a substantially larger concrete area (the forces are projected at a more upward angle, and, therefore, traverse more concrete over a substantially increased area) as compared to the expansion forces that result from a clay-based water seal having a 90° angle at the uncured concrete-surrounded corner(s). In one preferred embodiment of the feature described in the preceding paragraph, an expansion force passing through the uncured concrete, defined by the water seal expansion forces, and a plane perpendicular to a planar lower surface of the water seal article that passes through an upper corner (s) surrounded by uncured concrete (defined by the intersection of a side surface of the article and the upper surface of the article), form an angle of less than 45°. The shaped water sealing article of the present invention can have a number of shapes while increasing the quantity of concrete that fields the expansion forces of an expandable water seal article, so long as one or both upper, elongate corners of the article that contact uncured concrete have an included angle greater than 90°, preferably 100° or greater. The invention will now be further described by way of example with reference to the accompanying drawings, in which:- Figure 1 is a partially broken-away perspective view of the shaped water-sealing article of the present invention, in the form of an elongate trapezoid; Figure 2 is a partially broken-away perspective view of the shaped water-sealing article of the present invention, in the form of an elongate trapezium; Figure 3 is a partially broke-away perspective view showing the trapezoidally shaped water-sealing article of Figure 1 disposed between two vertically aligned concrete sections; Figure 4 is a partially broken-away perspective view showing forces applied to a surrounding uncured upper concrete section, by the expansion of the trapezoidally-shaped article of Figure 1; Figure 5 is a partially broken-away perspective view, similar to Figure 4, showing forces applied to a smaller area of the same upper concrete section by the expansion of a rectangular-shaped prior art water-sealing article; and Figures 6 and 7 compare initial hydration of the prior art rectangular water-sealing article to hydration of the trapezoidal water-sealing article of the present invention. Referring now to the drawings, a shaped article 10 of the invention can be in the form of a trapezium (Figure 2), having no parallel upper, lower and side surfaces; or the article 12 (Figure 1), preferably, is in the shape of a trapezoid having planar, horizontal upper (top) and lower (bottom) surfaces. Referring now specifically to Figure 1, the trapezoidally-shaped water seal article 12 includes a base or bottom planar surface 14 for adherence to a planar surface, e.g., of another cured concrete section, preferably having a width of about 1.905cm to about 5.08cm (about ¾ to about 2 inches) most preferably about 3.175cm (about 1.25 inches); a parallel, horizontal upper surface 16 having a width of about 1.27cm to about 2.54cm (about 0.5 to about 1.0 inch), e.g. preferably about 1.778cm (about 0.7inch) wide; and two side surfaces 18 and 20 having a vertical height of about 0.635 to about 2.54cm (about 0.25 to about 1 inch), preferably about 1.27cm (about 0.5 inch), disposed at an included angle of about 30° to about 80° from the horizontal lower surface 14, to provide an included angle of about 100° to about 150° at the corners c 1 and c 2 defined by the intersection of side surfaces 18 and 20, respectively, with the upper surface 16. A scrim or netting material 22 preferably is secured to and is coextensive with the upper surface 16 for better securement of concrete nails driven vertically through the article 12 from the upper surface 16. Alternatively, the water seal article 12 can be adhesively secured using an adhesive, without the netting material 22, to prevent displacement of the water seal article while pouring an additional concrete section thereover. Referring to Fig. 2, the shaped water seal article has a cross section in the shape of a trapezium including a planar, horizontal base or lower surface 24, an upper surface 26, and two non-parallel side surfaces 28 and 30 to provide a single. uncured concrete-contacting corner c 3 having an included angle α, as defined with reference to Fig. 1, preferably about 130°. The clay water seal preferably includes about 35% to 90% by weight water-swellable bentonite clay, such as sodium bentonite, about 10% to 65% by weight polypropene, polybutene, or mixture thereof, and optionally about 1% to about 20%, e.g., about 5% by weight of an elastomer, such as partially cross linked butyl rubber. For avoidance of doubt it is confirmed that the expression polybutene as used throughout the specification including the claims, includes polyisobutylene. Examples of compositions useful in forming the clay water seal articles of the present invention include, for example, the compositions disclosed in U.S. Patent Nos. 4,534,925; 4,534,926; and 4,787,780, all of which are incorporated herein by reference. The clay seal is made of a non-toxic material, requiring no special handling equipment and does not contain any material that discolors or irritates the skin. As shown in Figure 3, the water seal article, e.g., 12, is disposed such that the planar, lover surface 14 overlies an at least partially cured lower concrete Section 32, and an uncured concrete section 34 then is poured onto the lover concrete section 32, over the article 12. The at least partially cured concrete section 32 may be disposed underneath and in contact with the uncured, second concrete section 34, or the sections 32 and 34 may be laterally disposed with the water sealing article 12 disposed along an interface of the two sections 32 and 34. The water-swellable clay-containing water seal article of the present invention preferably is in the form of a flexible strip and is easily and efficiently installed by a single laborer. The seal may be supplied in the form of a coiled elongate strip that is unwound when applying the article between adjacent concrete sections. No split forming or splicing is required as may be required with other waterstop articles. Preferably, the clay-containing water seal article of the present invention is adhered to the butt end of an at least partially cured section of concrete 32 and, preferably, is positioned a minimum of 5.08cm (2 inches) from the exterior joint surface (i.e., there should be a minimum of 5.08cm (2 inches) of concrete separating the water-swellable clay-containing sealing article 10 or 12 from the exterior sides 40 and 41 of the joint--see Fig. 3). The article 10 or 12 preferably is nailed or adhesively secured to the cured concrete section 32, e.g., using concrete nails 42, before pouring the second concrete section 34. Nailing down the clay seal in this manner will aid in preventing displacement of the clay seal during pouring of the concrete 34. Preferably, an end surface 44 of the article 12 should abut an end of a previously placed strip, and the strips should not overlap. Following positioning and optional nailing of the article 12 to an at least partially cured concrete section 32, the second section of concrete 34 is poured to surround article 12, except for its bottom surface 14 in contact with lower concrete section 32, and onto an upper surface, or adjacent a side surface, of concrete section 32 to complete the joint. As shown in Figures 4 and 5, the developing expansion forces along planes 50 and 52, resulting when using the water-sealing articles of the present invention, are absorbed along substantially larger planes in the newly poured concrete, and at a substantially more upward angle from the corners C 1 and C 2 than the forces absorbed along planes 60 and 62, resulting from expansion of a rectangular or square-cornered prior art water-sealing article 63. As a result, expansion of the water seal articles of the present invention will be more easily absorbed by the curing concrete. In addition, the clay water sealing articles or the present invention will waterproof the concrete joint, preventing water from traversing any spaces 65 (Figures 3 and 4) between the concrete sections 32 and 34. Upon hydration, the clay water seal article expands, preferably to many times its non-hydrated volume, to form a water-impenetrable clay seal that completely prevents water from passing through the article. In accordance with another important advantage of the water seal articles of the present invention, the angled lower elongate edges, as shown forming angles β 1 and β 2 in Figure 2, are less than 90°, preferably about 45° to about 80°. Hydration of this lover edge at the acute angle β 1 and/or β 2 , upon contact with water, permits the water seal article to hydrate at hydration volume H 1 , as shown in Figure 7, hydrating only a lower corner of the product. An article having a 90° lower angle β 3 , as shown in Figure 6, permits hydration vertically upwardly, over hydration volume H 2 , resulting in greater forces acting on the newly formed concrete, along force planes 60 and 62 (Figure 5) over a smaller newly poured concrete volume V 2 (Figure 5), versus volume V 1 for the articles of the present invention. The clay water seal article of the present invention may be used in all environmental temperatures encountered at the installation location without becoming too stiff or brittle in cold temperatures, and without becoming too soft at higher temperatures. There is no need to heat the water seal article in cold temperatures to give it sufficient flexibility, and the water seal article remains totally flexible over time without shrinking, substantially hardening or oxidizing.

Claims: A plurality of water-sealed concrete sections comprising: a first section (32) of at least partially cured concrete; a second section (34) of substantially uncured concrete; and a shaped water-sealing article (12), disposed between said first section (32) and said second section (34) to prevent water penetration between said two concrete sections, said shaped water sealing article (12) containing at least about 20% by weight of a water-swellable bentonite clay, and having a quadrilateral cross-sectional shape having an upper surface (16;26), two side surfaces (18,20;28,30) and a bottom surface (14,24) whereby, upon hydration of the article when said article is in position between said concrete sections, expansion forces are absorbed by said second concrete section (34), said forces extending upwardly and outwardly from an edge (C1, C2; C3) of said water sealing article that is surrounded by said second concrete section, said edge (C1, C2; C3) having an included angle of at least 100°, said edge defined by an intersection of one of said side surfaces (18,20;28,30) of said article and said upper surface (16;26) of said article (12). A plurality of water-sealed sections as claimed in claim 1, wherein said water-swellable clay of said water sealing article comprises about 35% to about 90% bentonite clay and about 10% to about 65% polypropene, polybutene, or mixture thereof. A plurality of water-sealed sections as claimed in claim 1 or 2, wherein said plane of expansion forces and a line perpendicular to a planar bottom surface (14;24) of said article (12), said line passing through said edge (C1,C2;C3), form an angle less than 45°. A plurality of water-sealed sections as claimed in any one of the preceding claims, wherein said at least partially cured concrete section (32) is disposed below and in contact with said section (34) of substantially uncured concrete. A plurality of water-sealed sections as claimed in any one of the preceding claims, further including a mesh scrim (22) secured to the upper surface (16) of said water-sealing article (12), and essentially coextensive with said upper surface. A plurality of water-sealed sections as claimed in any one of the preceding claims, wherein said included angle of said water-sealing article (12) is in the range of about 100° to about 150°. A plurality of water-sealed sections as claimed in any one of the preceding claims, wherein said included angle of said water-sealing article (12) is in the range of about 120° to about 140°. A plurality of water-sealed sections as claimed in any one of the claims 1 to 6, wherein said included angle of said water-sealing article (12) is included in the range of about 110° to about 140°. A plurality of water-sealed sections as claimed in any one of the preceding claims, wherein said included angle of said water-sealing anticle (12) is about 130°. A plurality of water-sealed concrete sections as claimed in any one of the preceding claims, wherein said water-sealing article (12) has a trapezoidal shape having a wider base (14) in contact with said first section (32) of concrete, and having a narrower, parallel upper surface (16) surrounded by said second concrete section (34), wherein at least one upper edge (C1,C2) of said trapezoid has an included angle in the range of at least 100°. A plurality of water-sealed concrete sections as claimed in claim 10, wherein said included angle is in the range of from about 100° to about 150°. A method of waterproofing an area of potential water leakage between a plurality of adjacent sections (32,34) of concrete comprising: forming a first section (32) of at least partially cured concrete; disposing the shaped water-sealing article (12) as defined in any one of the preceding claims adjacent to and in contact with said first concrete section (34); and forming a second section (34) of substantially uncured concrete in contact with said first concrete section and surrounding the upper edge (C1, C2; C3) of said water-sealing article (12). A method as defined in claim 13 wherein: said water-sealing article (12) creates expansion forces extending into said second concrete section (34) upwardly and outwardly from said edge (C1,C2;C3); and said expansion forces being absorbed by more of said second concrete section (34) than if the water-sealing article (12) has a 90° included angle at said edge, thereby lessening the effect of the expansion forces against the second concrete section.

Inventors: KANGAS WILLIAM W, KANGAS, WILLIAM W.
Applicants: AMCOL INTERNATIONAL CORP, AMCOL INTERNATIONAL CORPORATION
Application year: 1994
Main classification: E02B3
IPC codes: E02B3, E02D29, E04B1